The asymmetric synthesis of (+)-sitophilure, the natural form of the aggregation pheromone of Sitophilus oryzae L. and Sitophilus zeamais M.

Abstract

A forma natural do (+)-sitofilure, feromônio de agregação de Sitophilus oryzae L. e Sitophilus zeamais M., foi preparada em 12 etapas, 18% de rendimento total e 82% de excesso enantiomérico a partir da redução microbiológica de 3-oxopentanoato de metila com S. cerevisiae na presença de cloroacetato de etila.The asymmetric synthesis of (+)-sitophilure, the aggregation pheromone of Sitophilus oryzae L. and Sitophilus zeamais M., was carried out in 12 steps, 18% overall yield and 82% enantiomeric excess from the enzymatic reduction of methyl 3-oxopentanoate with S. cerevisiae in the presence of ethyl chloroacetate.

Diastereoselective Chelation-Controlled Additions to β-Silyloxy Aldehydes

“…Interestingly, in the absence of EtZnX Lewis acids, the reaction of diethylzinc (1.2 equiv) with ( R )-3-TBS-2-methylpropanal 1 provided the chelation controlled product with 3.5:1 dr in < 10% yield (Table 1, entry 1). The absolute stereochemistry of the major diastereomer was ascertained through comparison to literature data 16 and confirmed by modified Mosher ester analysis. 17 To achieve synthetically useful diastereoselectivities and yields, Lewis acids that could chelate the substrates were utilized.…”

Insect pheromone synthesis in Brazil: an overview

“…In the same work, the addition of the boron enolate of 3-pentanone to propionaldehyde, followed by oxidative treatment, afforded a 9:1 mixture of (4SR, 5RS)-and (4SR, 5SR)-8, in 43% overall yield (Scheme 7). Pilli and Riatto 43 described later an asymmetric synthesis of (+)-sitophilure (8). The synthesis was carried out in 12 steps, in 18% overall yield and 82% enantiomeric excess, with the enzymatic reduction of methyl 3-oxopentanoate with S. cerevisiae in the presence of ethyl chloroacetate being used to generate the key chiral synthon (Scheme 8).…”

Biocatalysis Applied to the Synthesis of Pheromones

“…The asymmetric synthesis of (+)-sitophilure (34), the aggregation pheromone of Sitophilus oryzae L. and Sitophilus zeamais M., was carried out by means of the enzymatic reduction of methyl 3-oxopentanoate with bakers' yeast [172].…”